Process for assembling a snubbing arrangement in a railway truck

ABSTRACT

A process for assembling a snubbing arrangement in a railway truck where the truck includes a bolster interconnecting a pair of side frames and a pair of friction shoes in inclined bolster pockets at each end of the bolster and cooperating with vertical surfaces in each side frame. The process includes the steps of assembling the friction shoes in the bolster pockets, inserting a torsional spring means in an unstressed condition into the bolster with a central portion engaging the bolster and end portions engaging the friction shoes, inserting the bolster, spring means and friction shoes into the respective side frame, and imparting a constant load on the spring means by urging the central portion away from the bolster so as to urge the friction shoes upwardly into the pockets and outwardly into snubbing engagement with the vertical surfaces of the side frame.

United States Patent 1 Tack [ 1 Feb. 20, 1973 [54] PROCESS FORASSEMBLING A SNUBBING ARRANGEMENT IN A RAILWAY TRUCK [75] Inventor: CarlE. Tack, Elmhurst, Ill.

[73] Assignee: Amsted Industries Chicago, 111.

[22] Filed: Jan. 4, 1971 [21] Appl. No.: 103,424

Incorporated,

Related US. Application Data [63] Continuation-impart of Ser. No.736,420, June 12,

1968, Pat. No. 3,575,117.

2,827,987 3/1958 Williams ..l05/197 D Primary ExaminerCharles W. LanhamAssistant ExaminerV. A. Dipalma Attorney-Walter L. Schlegel, Jr. andRussell W. Pyle [57] ABSTRACT A process for assembling a snubbingarrangement in a railway truck where the truck includes a bolsterinterconnecting a pair of side frames and a pair of friction shoes ininclined bolster pockets at each end of the bolster and cooperating withvertical surfaces in each side frame. The process includes the steps ofassembling the friction shoes in the bolster pockets, inserting atorsional spring means in an unstressed condition into the bolster witha central portion engaging the bolster and end portions engaging thefriction shoes, inserting the bolster, spring means and friction shoesinto the respective side frame, and imparting a constant load on thespring means by urging the central portion away from the bolster so asto urge the friction shoes upwardly into the pockets and outwardly intosnubbing engagement with the vertical surfaces of the side frame.

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PROCESS FOR ASSEMBLING A SNUBBING ARRANGEMENT IN A RAILWAY TRUCK This isa continuation-in-part of my application Ser. No. 736,420, filed June12, 1968, now U.S. Pat. No. 3,575,] 17.

This invention relates to snubbing arrangements for railway vehicles andmore particularly to a process for assembling a snubbing arrangementutilizing friction shoes operatively carried in wedge-shaped pockets atopposite sides of a truck bolster structure, wherein the friction shoesare urged into sliding frictional contact with wear plates mounted onthe vertical columns of the side frames of the truck.

Two primary concepts have developed in the use of a spring force to urgefriction shoes into engagement with the side frame columns and otherfrictionsnubbing surfaces of the truck. One concept involves theapplication of a spring under compression between the bolster and thefriction shoe mounted in the bolster structure. In the usualconstruction, the friction shoe is borne upwardly against the inclinedwalls of pockets formed in the bolster and outwardly against the sideframe columns, the spring exerting a substantially constant forceagainst the friction shoe regardless of vertical movements of thebolster. The spring may be mounted under compression in a cavity withinthe friction shoe or in other locations, but space limitations anddifficulties of installation have sometimes presented problems in theuse of such arrangements.

The other concept involves the application of one or more controlsprings under compression between a member of the truck side frame andthe friction show operatively mounted in the bolster. Since the truckbolster supports the weight of the car body and is resiliently supportedin the side frames, the force exerted on the friction shoes is variableand increases as the weight on the bolster increases. Because of spacelimitations and the tendency of such control springs to take permanentset after use over a period of time, this type of arrangement cannotprovide adequate control forces under all conditions of load and normalwear of friction elements.

An object of this invention is to provide a process for assembling asnubbing arrangement in a railway truck utilizing a unique constanttorsional spring force that may be used either in conjunction with avariable compression spring force or alone.

Another object of this invention is the provision of a process ofassembling a snubbing arrangement including a torsional spring to whichan independent torsional load is applied after installation of suchspring.

Other objects will become apparent from the following description andappended claims, taken in connection with the accompanying drawingswherein;

FIG. 1 is a fragmentary elevational view, partly in section, of arailway truck that incorporates features of the presently describedinvention;

FIG. 2 is a fragmentary side view of a portion of the bolster thatincorporates features of the present invention;

FIG. 3 is a fragmentary plan view of the bolster shown in FIG. 2;

FIG. 4 is a plan view of the torsional spring utilized in the preferredembodiment of the present invention; and FIG. 5 is an elevational viewof the wedge utilized with the torsional spring described herein.

With more particular reference to FIG. 1, the improvements of thepresent invention are shown embodied in a railway car truck whichgenerally comprises a pair of side frames, one of which 10 is shown,interconnected by a bolster 12 resiliently supported at its ends onspring groups 14. Each side frame 10 includes a top or compressionmember 16 and a bottom or tension member 18 interconnected by spacedvertical columns 20 which together define an opening to receive the endof the bolster 12.

Inasmuch as the opposite sides of the truck herein shown includeidentical parts, the drawings and description, for the sake of brevity,will be confined to one side of the truck, it being understood that acomplete truck includes like parts at both sides thereof.

As best shown in FIGS. 1-3, the snubbing arrangement generally comprisesa pair of wedge-shaped pockets 22 (FIG. 3) formed in opposite sides ofthe bolster 12 near the end thereof, said pockets opening outwardlytoward the side frame columns 20 and having an inclined wall 24. Afriction shoe 26 is operatively carried in each pocket 22, and includesan inclined surface 28 corresponding to and frictionally engaging theinclined wall 24 of the pocket, as well as a vertical surface 30 forfrictionally engaging vertical wear plates 32 mounted on the side framecolumns 20.

As shown in FIG. 1, if a variable spring force on the friction shoes isdesired, this maybe accomplished by the use of one or more controlsprings 34 extending between the friction shoe 26 and a correspondinglocation on the tension member 18 of the side frame 10. The controlspring 34 serves to urge the friction shoe 26 upwardly into wedgingengagement between the inclined wall 24 of the bolster pocket 22 and thewear plate 32 on the side frame column 20.

As illustrated in FIGS. 1-4, a constant spring force on the frictionshoes is provided by a helical torsional spring 36. As best shown inFIGS. 2-4, this spring includes two separate helical portions 38arranged around a common horizontal axis and interconnected by aU-shaped portion 40 extending away from said axis. The free ends of thehelical portions 38 terminate in respective substantially straightextensions 42, which also extend away from the horizontal axis of thespring. As will be hereinafter more fully explained, the U- shapedportion 40 forms a convenient lever to which a torque may be separatelyapplied for imparting a torsional load to the entire spring, whichcauses the extensions 42 to act as resilient levers for engaging andurging the friction shoes 26.

As shown in FIGS. l-3, the torsional spring 36 is placed in operativeposition by first inserting the end extensions thereof 42 throughrespective elongated vertical slots 44 in the outboard sides of thepockets 22 on both sides of the bolster and into a respective cavity 46formed within each friction shoe 26. When so inserted, the torsionalspring 36 is designed such that the helical and U-shaped portionsthereof, 38 and 40, respectively, will lie on the bottom wall 48 of thebolster 12, while the end extensions 42 will be engageable withrespective friction shoes 26 within the respective cavities 46 thereof.It will also be noted that the spring is installed in a substantiallyunstressed condition, thereby greatly facilitating its insertion andremoval.

The cavity 46 of the friction shoe 26 is provided with a transversevertical wall 41 extending from the top of said cavity downwardly for aportion of the height of said cavity and extending between the walls ofthe inclined surface 28 and the vertical surface 30 of the frictionshoe. As shown in FIGS. 1 and 2, the end extensions 42 of the torsionalspring 36, when in operative position, are engageable with the lowersurface of the transverse vertical wall 41. The transverse vertical wall41 also serves the useful function of providing additional internalsupport for the friction shoe 26.

Means are provided for applying a torsional load to the torsional spring36 after its installation which means may comprise a wedge, generallyindicated at 50, which is inserted or driven between the U-shapedportion 40 of said spring and the bolster bottom wall 48 after saidspring has been placed in position. As best shown in FIG. 3, the wedge50 includes a pair of spaced legs 52 that straddle the central verticalweb 54 of the bolster. When viewed from the side, as shown in FIG. 5,the wedge 50 may be seen to include an upper inclined portion 56 slopingupwardly to merge with a horizontal portion 58 upon which the U-shapedportion 40 of the torsional spring 36 rests when in assembled position.The wedge 50 also includes a raised head 60 and an upwardly inclined toe62, which prevent the spring 36 from becoming dislodged during and afterassembly. A locking lug 64 may be provided on the bottom of the wedge 50to engage and lock with a corresponding cavity 66 (FIG. 2) upon assemblyof said wedge.

When the wedge 50 is installed, a torque is applied to the U-shapedportion of the torsional spring 36, thereby imparting a torsional loadto said spring, which causes the free end extensions thereof 42 to beurged upwardly against the internal transverse vertical wall 41 of eachfriction shoe 26. A constant force is thereby applied to urge thefriction shoe 26 upwardly into wedging engagement between the inclinedwall 24 of the bolster pocket 22 and the wear plate 32 of the side framecolumn 20. It may thus be seen that the torsional spring and wedgearrangement may be used alone or in combination with the variable springforce herein before described.

Assembly of the bolster and friction parts into the side frame ispreferably carried out as follows: The friction shoes 26 are firstinserted into the bolster pockets 22 and are held therein by insertionof the torsional spring 36, as previously described, in substantiallyunstressed condition. The end of the bolster 12 is then inserted intothe enlarged lower portion of the opening between the side frame columnsand is raised upward to allow assembly of the subjacent spring groups 14and 34. A torsional load is then applied to the torsional spring 36 ashereinbefore described. In its unstressed condition, the assembledtorsional spring serves to hold the friction shoes in their respectivepockets during assembly of the bolster into the side frames. The truckmay be disassembled by reversing the above procedure.

friction surfaces, said bolster having pockets with inclined surfaces toreceive friction shoes for snubbing engagement with said frictionsurfaces, said process comprising positioning unitary spring means in anunstressed condition with a central portion in engagement with saidbolster and with end portions in engagement with respective frictionshoes, and then imparting a constant load to said spring means by urgingthe central portion away from said bolster to thereby urge said frictionshoes upwardly against the inclined surfaces and outwardly intoengagement with the friction surfaces of the side frame.

2. The process according to claim 1 wherein the step of imparting a loadto said spring means comprises inserting a wedge between a surface onsaid bolster and the central portion of said spring means.

3. A process for assembling a snubbing arrangement in a railway truckhaving a side frame connected to a bolster, one end of said bolsterbeing received in a window defined by an opening between columns of saidside frame, said bolster having downwardly opening pockets carryingfriction shoes for snubbing engagement with respective side framecolumns, said process comprising first assembling the friction shoes inthe bolster pockets, holding said friction shoes in said pockets whileplacing a torsional spring means in unstressed condition with a centralposition in engagement with said bolster and with end portions inengagement with the respective friction shoes such that the frictionshoes are held upward in said pockets, then assembling the bolster,torsion spring means and friction shoes into the window of the sideframe, and then applying a constant torsional load to said torsionalspring means by urging the central portion thereof away from the bolsterin such a manner as to urge said friction shoes into engagement withrespective side frame columns.

4. The process according to claim 3 wherein the step of imparting atorsional load to said spring means comprises inserting a wedge betweena surface on said bolster and a central lever portion extending fromsaid spring means.

5. In a method of assembling a snubbed railway truck wherein a bolsteris spring-supported by a side frame having a friction surface, andwherein a friction shoe engages said friction surface and also engagesan opposed wedge surface of the bolster; the steps of engaging the shoewith said surfaces, engaging an actuator spring with said shoe and saidbolster with the actuator spring in unstressed condition, and thenstressing the actuator spring to urge the shoe against said surfaces byinserting a member between and abutting portions of the spring and thebolster.

1. A process for assembling a snubbing arrangement in a railway truckhaving a side frame and a bolster received in an opening of the sideframe defined by friction surfaces, said bolster having pockets withinclined surfaces to receive friction shoes for snubbing engagement withsaid friction surfaces, said process comprising positioning unitaryspring means in an unstressed condition with a central portion inengagement with said bolster and with end portions in engagement withrespective friction shoes, and then imparting a constant load to saidspring means by urging the central portion away from said bolster tothereby urge said friction shoes upwardly against the iNclined surfacesand outwardly into engagement with the friction surfaces of the sideframe.
 1. A process for assembling a snubbing arrangement in a railwaytruck having a side frame and a bolster received in an opening of theside frame defined by friction surfaces, said bolster having pocketswith inclined surfaces to receive friction shoes for snubbing engagementwith said friction surfaces, said process comprising positioning unitaryspring means in an unstressed condition with a central portion inengagement with said bolster and with end portions in engagement withrespective friction shoes, and then imparting a constant load to saidspring means by urging the central portion away from said bolster tothereby urge said friction shoes upwardly against the iNclined surfacesand outwardly into engagement with the friction surfaces of the sideframe.
 2. The process according to claim 1 wherein the step of impartinga load to said spring means comprises inserting a wedge between asurface on said bolster and the central portion of said spring means. 3.A process for assembling a snubbing arrangement in a railway truckhaving a side frame connected to a bolster, one end of said bolsterbeing received in a window defined by an opening between columns of saidside frame, said bolster having downwardly opening pockets carryingfriction shoes for snubbing engagement with respective side framecolumns, said process comprising first assembling the friction shoes inthe bolster pockets, holding said friction shoes in said pockets whileplacing a torsional spring means in unstressed condition with a centralposition in engagement with said bolster and with end portions inengagement with the respective friction shoes such that the frictionshoes are held upward in said pockets, then assembling the bolster,torsion spring means and friction shoes into the window of the sideframe, and then applying a constant torsional load to said torsionalspring means by urging the central portion thereof away from the bolsterin such a manner as to urge said friction shoes into engagement withrespective side frame columns.
 4. The process according to claim 3wherein the step of imparting a torsional load to said spring meanscomprises inserting a wedge between a surface on said bolster and acentral lever portion extending from said spring means.